Any way you cut it, GM is going for blood with the new and improved 2009 Cadillac CTS-V and word from engineers of an unofficial rating of at least 550 HP only furthers that point. It takes a lot to make the BMW M5 look like a chump, but a 50 HP advantage will do a thing like that. Of course, the engine hasn't gone through SAE certification yet, and based on GM's history of underselling the power output on its recent engines, Edmunds Inside Line is extrapolating a 567 HP figure out of the LS9 mill. We would never go so far as to speculate on numbers, but we will wring our hands in delighted anticipation.